Cache issue on iPhone/iPad for iPhoto themed attachments

I have a problem that has been driving me nuts! And I've searched the Internet high and low to no avail. Basically, my wife loves sharing our photos in iPhoto with friends and family. She particularly likes the "themes" in iPhoto 11 (aka Corkboard, Collage, etc). When she uses the "Mail" option within iPhoto, it launches Mail.app. All cool so far. What appears to happen is that the email that is generated attaches her photo "collage" to the email as a .zip file which is always named "Pictures.zip."

The issue occurs when trying to view these emails on an iPhone or iPad. The first email is able to be viewed correctly. If she has sent a few of these, all subsequent emails have the same photos that were attached to the first email that was opened. In effect, it seems like the iPhone or iPad has cached the first Pictures.zip, and continues to display the same file, even though it is a different, subsequent email.

One "fix" is to terminate the mail app on the iPhone, reopen it, and then proceed to the second email. But this is obviously tedious for multiple emails.

Viewing these same exact emails on my Mac (Mail.app) or via a browser (webmail) does not exhibit the same behavior.

So the questions are:

1. Anyone else ever seen this issue?

2. Anyway to disable the caching on the iPhone/iPad?

3. Any way in either iPhoto or Mail.app to make this issue go away?

Thanks in advance,

Rob